


Test Subject

by DeckofDragons



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Amalgamate Porn, Bondage, Cum Inflation, Dehumanization, Double Eye Socket Fucking Combined with Mouth Rape, Drugs, Eye socket fucking, Forced Arousal, Gross Dicks, Gross Porn, Injections, Knotting, Medical Kink, Mouth rape, Muzzle, Needles, Non-Con Breeding, Other, Tentacle Rape, Trypanophobia, Voyeurism, cum kink, disgusting porn, possible pregnancy, straight jacket
Language: English
Status: Completed
Published: 2018-06-23
Updated: 2018-06-24
Packaged: 2019-05-27 07:40:24
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 2
Words: 6,858
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15019862
Author URL: https://archiveofourown.org/users/DeckofDragons/pseuds/DeckofDragons
Summary: Sans has unfortunately become one of Gaster's test subjects.





	1. Needle

**Author's Note:**

> This was inspired by this: https://parknewna.tumblr.com/post/166359244194/i-love-sans-being-gasters-experiment
> 
> That series of pics brought to my mind the beautiful mental image of Gaster watching calmly and taking notes as something horrible happened to Sans in the name of science. I chose that horrible thing to be amalgamate rape because I wanted to make it as horrifying as I could and because I like amalgamate porn and want there to be more of it.
> 
> Also this is my 69th Undertale fic. Yay!

Sans groaned, blinking his eyes to try to clear his vision. Everything was a dizzying blur of bluish grey and too bright light. It made him nauseous.

Where was he? What had happened last? … He couldn’t remember. He wanted to lift his hands to his face to rub at his eye sockets but… they wouldn’t move. They were bound in something, held to his lower chest in an almost crossed arm position. He tugged them in opposite directions but it was no use, they were securely bound together

There was something on his face too. It wrapped around to the back of his skull and covered his mouth. The front part was cold and metallic feeling against his bones, heavy too, the bands keeping it on his face were softer and warmer, perhaps made of leather.

He closed his eyes and shook his head, trying to rid his mind of the fog it was under and clear his vision. It worked, sort of, when he opened his eyes again the blueish grey blur resolved itself into the sight of a small room that looked suspiciously like a sterile hospital room. Blue gray tiling for the floor and a matching paint job for the walls, there was surgical lamp next to the chair he was sitting in with a covered medical table next to it.

Sans’ clothing was gone, other than whatever he was wearing that kept his arms together and close to his chest – it suspiciously resembled a straightjacket – he was naked. His bare ankles were strapped to the chair legs with what again felt like leather, set so that his legs were slightly spread apart. He could maybe try to stand but there’d be no point if he couldn’t walk away from the chair. Who had done this to him? And more importantly what were their plans for him once they returned?

He gathered his magic for a teleport but wasn’t surprised when he got a jolt of pain in his soul as his magic wasn’t allowed to function instead. No sane person would kidnap a monster without a magic blocker or some other way to incapacitate their victim. Which given Sans’ lack of physical strength and small stature put him at a major disadvantage even without the straight jacket, muzzle, and straps around his ankles.

 He struggled some more against his bindings instead but it was futile. He was too weak to ever hope of breaking them even if given unlimited time to do so. Which he didn’t have, his captor would probably return any minute now. So, it was best to relax as much as possible and wait.

He was in luck – or perhaps unlucky, depending on what was about to happen to him – the door opened not even five minutes later. It was… Gaster? Sans’ boss. He’d always been a creepazoid but this was a whole other level. He glided in, having his ever present magic floating hands close the door behind him.

He’d always been a tall monster but now seemed even taller. His deep black cloak seemed specifically designed to be as intimidating as possible. And the cracks in his skull – one running up from his eye socket, the other running down from the other socket to his mouth –gave him a lopsided look that made Sans fell uncomfortable under his gaze at the best of times – relatively speaking anyway, there were no good times when Gaster was in the room, especially when he was paying any kind of attention to Sans.

“Good afternoon Sans,” he said, his voice velvety smooth and professional. He almost sounded like he was just greeting Sans in the hallway or at the watercooler.

Sans couldn’t even cuss him out for it because of the damn muzzle on his face. He growled instead, glaring at Gaster to hide his fear – normally small when dealing with Gaster under normal circumstances but now much bigger.

Gaster raised an ‘eyebrow’, making his face contort unpleasantly. “There is no need to get angry.”

If Sans wasn’t muzzled he’d have some choice things to say in response, most of them vulgar. Instead he was forced to sit in silence as Gaster pulled his spectacles out of his cloak to place on his face, securing them with magic. He was about to do an experiment and would record his findings using the clipboard and pen he pulled out of his cloak next.

While he was doing that his summoned hands – identical to his real ones, complete with holes in the palms – pulled aside the cloth covering the medical table. On it was basic medical things including a large needle.  Its syringe was filled with a cloudy liquid and the pointed end of its shaft was capped with plastic.

The hands picked it up and flicked the syringe part a few times to rid it of air bubbles before popping the cap off. Then they floated over to Sans. Unable to take his eyes off them, he leaned as far away from them as the armrests on the chair allowed, which unfortunately wasn’t far. But all he accomplished was making it a little easier for one of the hands to unzip one of his sleeves, starting from his shoulder down to where his forearm was bound to the other.

He the hand holding the needle lined it up with his now bare shoulder. The other hand floated up to hold the top of his skull, using more than enough force to keep him still.

His breathing was loud and echoey inside the muzzle as the tip of the needle pressed against his bone. It was cold and sent a shiver through him. What was in the syringe? What would it do to him? Would it hurt? Could it even pierce deep enough to his bone to eject into his magic? If so how long would it take for _it_ to affect him in whatever way it was going to affect him?

The needle scraped against his bone, making a _horrible_ sound that was made no better by how quiet it was. It was pressing down and … nothing was happening. Maybe it couldn’t pierce through after all.

“Hmm, I might not have thought this all the way through,” Gaster said. He was still holding his clipboard and pen with his real hands and was clicking the pen thoughtfully. Under ordinary circumstances it would’ve been annoying but right now it was the only thing that felt normal and real, unthreatening. “The rest of my test subjects have been fleshy monsters.”

Did that mean he was going to let Sans go? He couldn’t serve as a good test subject if the substance being tested couldn’t be injected into him, now could he? All this… bullshit had been for naught, thank _goodness_. Now all Sans would have to do was promise to never say anything about this ever again and it’d be okay. And as soon as he could he’d quit his job and run _all_ the way to the other side of the Underground and hopefully never see Gaster again. Dealing with the cold snow and barrenness of Snowdin was worth that.

“We’ll just have to inject the serum into some other way,” Gaster said, causally shattering Sans’ tentative hopes for freedom and getting out of this without suffering. He’d been foolish to even start to hope, this was Gaster, he wasn’t going to let something like biology of any creature get in the way of his experiments.

The hand holding the syringe pulled back as the other zipped his sleeve back up and two more popped into existence in front of Sans’ face. One grabbed onto the metal part of the muzzle while the other two pulled his head forward and went back around to mess with the straps and… undo them. Why though?

As the awfulness heaviness of the muzzle was pulled away from his face, Sans took a deep breath. He’d call for help as loud as he possibly could and hope someone would hear it and pray they’d both be willing and able save him but one of the hands shoved something into his mouth instead. A popsicle stick judging by the feel of it.

It pressed it to the roof of his mouth. Another hand grabbed the bottom of his jaw in a tight grip, preventing him from biting as the popsicle stick was forced back towards the rear of his mouth, stimulating his magic and making his tongue, throat, and everything else manifest in his mouth. He thrashed and gagged, unable to do anything about the invasion of his personal space. Part of him almost wished the needle in his arm had worked.

Something cold and hard squeezed the tip of his tongue and pulled it out as far as it would go; his sharp bottom teeth brushed up against the bottom of it. The popsicle stick was withdrawn, so was the hand holding his jaw open; he wouldn’t bite his own tongue and couldn’t dispel it while it was being held by something.

“There, that’s much better,” Gaster said, sounding as if he were talking about a minor problem he’d encountered with his scientific equipment.

“Fuck you,” Sans said, his voice garbled to near incomprehensibility due to his tongue being held hostage out of his mouth. He’d have said more if it wasn’t for the hand holding the needle moving closer once more, making him yelp and attempt to jerk back instead. All he got was pain in his tongue; the hand had an iron tight grip on the tweezers, keeping it in place.

“Please no,” he said, or tried to say as the hand pressed the tip of the needle to the top of his tongue. It was _cold_ and its metallic taste almost made him want to throw up. It pressed into this ecto-flesh with a small prick of pain that wouldn’t have bothered him even a little under normal circumstance but made him squeak this time.  A second later the coldness of the needle in his tongue seemed to spread as the plunger was pushed down, releasing the substance into his magic, making it feel like he had a giant block of ice in his mouth.

Thankfully the hands pulled back. He whimpered and coughed as he fought the need the to tear up in misery and fear. The numbing cold in his mouth was spreading, it made his bones feel tingly and weird, dispelling his mouth bits only made it worse. Oh dear, what was about to happen to him? If it was death hopefully it would be quick and with little to no pain.

He looked back up at Gaster and opened his mouth to ask – or maybe beg for mercy, who knows – but before he could even attempt to make a single syllable the muzzle was pressed back to his face and the hands were redoing the leather straps.

“I don’t want to listen to your mouth,” Gaster said with a shrug in answer to Sans’ indignant look. “Your constant complaining in annoying.” Every _single_ time Sans had complained in the past it had been _completely_ justified, Gaster was evil and expected his employees to do awful horrible sometimes disgusting things lest they get fired. If only Sans _had_ gotten himself fired, he wouldn’t be in this damn situation. “It should take about five minutes to fully set ins, though it might be a little faster due to your small size. It might also affect you more strongly than the others for the same reason, we’ll see.” How many other people had he done this too and more importantly had they survived it? And even _more_ importantly would Sans?

The next few minutes were stressful and uncomfortably silent as Gaster stood there, watching Sans. He occasionally jotted down something on his clipboard in between clicking his pen in that way he always did; halfway between fast and slow.

The tingly cold spread to Sans’ soul and from there it quickly infected his whole body. It was starting to become warm especially where it was concentrating in his pelvis, drawing more and more magic there which only made it warmer. It solidified into… a pussy? It was hot and wet, aching with growing arousal. Was the drug _supposed_ to do that?

Gaster’s floating hands moved the bottom of the straightjacket up, revealing Sans’ pelvis to Gaster. With a passive expression on his face, he jotted another note on the clipboard. Meaning this was unfortunately all going as he’d planned otherwise he would’ve said something.

Maybe he was just testing the drug and wouldn’t _actually_ touch Sans like that. Maybe he wanted to know how long it would take for the affects to fade by themselves, which judging by the way Sans’ arousal was continuing to grow would be torture but better than being touched like that. … Yeah, and maybe Sans was a long-lost fairy prince from Neverland too.

The hands pushed up his shirt a little bit more to touch his midsection. When and why had he summoned that? They were comfortably cool on his heated ecto-flesh, making him want more.

“So far so good.” Gaster jotted some more things down on his notebook. He didn’t give a single solitary damn for Sans’ discomfort, fear, or torment. It was like Sans was one of the non-monster mice that sometimes ended up in the Underground that he liked to dissect while they were still alive.

It was almost enough to bring tears of fear to Sans eyes. He’d always known he meant little to Gaster but… he’d still believed that Gaster saw him as a fellow monster and would treat him as such _not_ as something to perform cruel sexual experiments on. Even if he _could_ beg for mercy he would get none, hence the muzzle so he couldn’t annoy Gaster with attempting to appeal to his nonexistent merciful side. He was just another test subject now and there was _nothing_ he could do about it.

A few minutes of silence passed as the arousal continued to set in, making Sans want to whine and whimper in need. He stopped himself though even as he trembled hard enough with a mix of fear and desire to make his bones rattle softly. The drug unfortunately did little to nothing to cloud his mind as he would’ve preferred, he didn’t want to be fully conscious and aware for what was about to be done to him. Heck, being out of it completely would’ve been good, that way he wouldn’t know the exact way he’d been violated.

“All right, time to move you to a proper testing chamber,” Gaster broke the silence, sounding detached and businesslike. Sans almost would’ve preferred maliciousness, that way Gaster would at least care about his suffering even if it was enjoying it.

The hands undid the straps around his ankles. He stood and… immediately lost his balance and landed on his face because he was unable to catch himself with his hands. And he couldn’t right himself without the use of his hands. Awesome. So he whimpered instead, hating whatever circumstances had led this.

The hands gripped onto his shoulders and pulled him back upright. “None of that,” Gaster said, giving him a disapproving frown.

He opened the door they exited out into a hall, the hands on Sans’ pushing him forward. The hall was another area of the lab Sans had never seen and it matched the previous room’s hospital aesthetic. In both directions the hall ended in closed metal doors, locked no doubt.

Gaster went straight across the hall and opened the door. His hands pushed Sans along and he was forced to walk in too or fall over and probably be dragged in. Walking was uncomfortable though with they way his magic burned with need in his pelvis.

The room was larger than the previous one, a little more than twice as big. There was an operating table in the middle of the room, complete with leather straps for conscious patients. Next to it was a small area with a console that was cut off from the rest of the room by clear probably bullet-proof glass. And built into the wall that the foot of the bed pointed to was what looked like a metal garage door. It rattled as if something large and heavy had pushed against it from the other side.

Sans froze in his tracks. Nope, he was _not_ dealing with whatever the fuck was in there not even in a million years. Without missing a beat though the hands on his shoulders tightened and lifted him a couple inches into the air. He kicked, thrashed, and growled to no avail as he was carried to the table and pulled up onto it so that he was lying on his back.

More hands popped into existence to hold him down. His legs were spread as wide as they could go – _not_ a good sign, considering his current drugged condition – and so that his ankles were pulled close to his body and secured with leather straps coming up from beneath the table. A large strap was secured around his chest, under where his arms were crossed. He was stuck again and about to be violated, probably by whatever was behind the garage door that was making it shake and rattle.

Ignoring his squirming and whining, Gaster bent over to examine the straps. He even put aside the clipboard to test them with his real hands, the closest he’d gotten to touching Sans possibly ever, certainly since this horrid nightmare had begun. Apparently satisfied he nodded in satisfaction before straightening and stepping back.

He then retrieved his clipboard and pen before turning around and leaving, closing the door behind him. Leaving Sans alone with is wretched misery and arousal and the rattling of the garage door.

What could be in there? Something horrible that was for sure and by the sound of it _large_. Would it really… fuck Sans though? Maybe it would just… kill him instead? Not ideal but perhaps better than the alternative? Depending on what it was and how badly it was going to hurt him.

The table let out a mechanical whir as slowly starting rising. Spooked, Sans looked around and saw that Gaster was in the observation area, standing at the console that likely had the controls for the table on it. Such was confirmed to be the case when he pressed a button and the table stopped moving.

He then pressed another button that triggered a loud screeching buzzer sound. Sans flinched, unable to cover his ‘ears’. Thankfully it was short but _not_ thankfully it was followed by a grating noise as the garage door started to lift.


	2. Demon Goo Dog

The rattling against the door increased as whatever was inside started pushing against it with renewed vigor. Until it was high enough for a large white… paw(?) to stick out from underneath it, followed by another as whatever it was struggled to fit under the gap. They made wet plopping sounds and looked to belong to an ooze monster other than for the vague shape of a dog paw.

_Whatever_ it was though did not bode well for Sans. Tears of fear came to his eyes as the door kept rising and more of the _thing_ was visible until it managed to get its head and shoulders in. The rest of it quickly followed and Sans screamed at the sight of its face, or lack thereof. Underneath its decidedly pointed dog ears was a gaping black hole that pulsated as it howled in triumph.

Its tail wagged hard enough that its entire goopy body shook as it bounded over to Sans. Sans screamed again as it loomed over him, thrashing against his bindings. It was huge, more than twice his size. It could eat him if it wanted to.

It jutted its head between his legs, putting its ‘face’ inches away from his pussy as if sniffing it. Its tail started wagging even harder. It sniffed up his body, pausing at his face. It growled, wet and horrible it sounded like it came from a demon dog whose domain was the darkest depths of the ocean.

Whimpering, Sans clenched his eyes shut, forcing out more tears. A thick wet substance dripped down onto his face, was it drooling? He didn’t _dare_ open his yes to find out, he didn’t want to know anyway.

Something gripped onto his muzzle and tugged up. He yelped as eyes fell open to see that wet goopy tendrils had emerged from the impenetrable blackness of its face. He thrashed his head from side to side as it kept tugging on the muzzle as if trying to get it off. Why would it want _that_?

“No, bad dog, leave that on.” Gaster’s voice was muffled by the intervening glass but unmistakable. “I don’t want to listen to him whine and complain.”

The ‘dog’ ignored him though and kept tugging at the muzzle, pulling Sans’ head up with it. It growled again as it kept tugging. Eventually its tendril things snaked down and pulled on the straps themselves, hard enough to make them stretch and after a few minutes filled with Gaster trying to get the ‘dog’ to leave the muzzle alone they snapped.

“Please don’t hurt me,” Sans whimpered as the dog tossed the metal bit off to the side. It made a loud clank wherever it landed. Sans didn’t look though, his eyes were locked onto the gaping maw of the demon dog above him as its tendrils snaked back into its face… for now. The table was positioned at the perfect height for it to loom over him and was the perfect width for it to not get in its way. “Have mercy _please_.” Could it even _understand_ him? If so, would it _listen_?

Its paws made heavy wet plopping sounds on the floor as it shifted its position over him, straddling him. It whined excitedly as it stilled. Surely it wouldn’t _really_ rape him, right? It was a demon goo dog, what would a demon goo dog gain from sex with a skeleton monster? And it was so _big_ , it could _break_ him and would definitely hurt.

_Something_ grew out of its body and pushed against Sans’ clit, something thick and disgustedly soft, like how he would imagine rotting flesh would feel like. Sans fought against his bindings and tried in vain to dispel his pussy but it was no use.

“Please no, please no, please no, please…” He cut off with a scream as it thrust in. It was _huge_ and its soft gooeyness meant it pressed _perfectly_ against every inch of his sensitive inner walls, filling him completely. His body convulsed with an orgasm from that alone, clamping even tighter around its _dick_ inside him. He sobbed and panted his way through it as the demon goo dog let out a wretched wet bark before pulling roughly back and slammed into him again, pulling yet another scream out of him.

The _awful_ sensation of its gooey ‘flesh’ sliding and pressing against the sensitive walls of his pussy made him gag even as it continued to stimulate his heated aroused magic with each hard thrust. He was going to climax again if this continued. Hopefully it would finish fast and then be done with him.

Though bolted to the floor the table rocked and creaked under the force of its thrust and Sans was forced back against the limits of his bindings. It hurt and just added to his _wretched_ misery and torture.

“ _Stop_ , please, please, Doc… _make it stop_. … I’ll do _anything_ … please just _make it stop_ ,” he screamed loud enough to make his ‘throat’ hurt, his words interspersed with yelps each time the demon goo dog’s dick slammed into him.

He turned his head to see Gaster watching from behind the glass. He looked… annoyed. He _didn’t care_ that Sans was getting brutally raped in front of him or that it was _his_ fault. He was just annoyed that Sans was screaming and begging for any tiny shard of basic decency from him. Sans sobbed.

The dog barked, loud and wet, right Sans face. Something emerged from the impenetrable blackness of its face hole. Bearing disturbing resemblance to a tentacle it was much thicker than the other things had been and was dripping with slime. It snapped down into Sans’ eye socket. He screamed in pain as it pierced through his magic. It was a tight squeeze and his eye socket might have broken if the tentacle wasn’t so soft and malleable.

He sobbed and screamed, thrashing uselessly as much as he was able as it pressed to the back of his skull. It was slimy, gooey, and far to soft, and _nothing_ was supposed to go into his skull but especially not things like _that_. But he as helpless to get it out as it pushed deeper in, folding against the back of his inner skull before… bursting back out through his _other eye_.

He screamed again, in pain and wretched misery. He was _blind_ , he couldn’t _see_. He couldn’t _move_. His entire world was its dick thrusting into him, the sensation somehow _even stronger_ now, and the tentacle _inside his skull_. His next scream was cut short by something, thick, slimy, and far too soft thrusting into his mouth. _The tentacle_. It slid against the roof of his mouth, stimulating his magic in there and getting it to form. It tasted foul like how rotten eggs smelled against his tongue.

He gagged and chocked as it thrust down his throat. If felt like _thick_ foul-tasting tar was being poured down his gullet, making him gag and choke all the harder. It pulling back out was _even_ _worse_ , though it would’ve been preferable if it slid _all_ the way out instead of just to entrance of his mouth before jamming back down his throat. And all the while the demon dog _kept fucking him_ , not losing its rhythm for even a second. And now it was fucking his entire face too.

He writhed and sobbed, unable to even scream anymore as his body kept choking on its tentacle. Everything _hurt_ , especially his eyes, even as the pressure of an upcoming climax built in his magic, each thrust of its foul goopy dick bringing him a little bit closer. _Fuck_ whatever drug Gaster had administered him.

When it hit, it was intense. Waves of pleasure washed through him that _at least_ felt good and counteracted the _awful_ sensation of its thrusting into him. It was over all too shortly though and he was fully aware of its cock inside him once. It was… leaking fluid? Thick fluid, similar to the consistency of it. Its tentacle was too. It burned his mouth and throat with how awful it tasted, _nothing_ could compare. His body and soul heaved, no vomit came up though. That wasn’t much of relief, the sensation of it thrusting down his throat as his body tried to throw up was _painful_ and would’ve brought tears to his eyes if they weren’t filled with tentacle dick.

And the pain didn’t stop there as more fluid leaked out and his body tried in vain to vomit _something_ up. He’d prefer it if the demon dog ate him; he’d rather die than take any more of _this_. That wasn’t an option though as its thrusting sped up, both in his mouth and in his pussy. It was making barely doglike whining sounds now too. It was almost done, it would come and then this would be over. Only it would come _inside_ _him_. Still though, he only had to endure this _torture_ for a little while longer.

It barked as it hilted itself roughly inside him. The base of its dick expanded just inside his pussy, making him jerk in pain as it twitched and there was suddenly warm thick fluid gushing into him. It had a similar texture and feel to the ‘dog’s’ dick, making it feel almost as if it were pouring itself into him; a _disgusting_ thought.

Its tentacle _thing_ came a second or two later. Part of it expanding at where it entered his mouth. And choked, gagged, and heaved again as _foul_ tasting thick _cum_ – that’s what it was, there was no beating around the bush – flooded against the back of his throat. Without him swallowing it, it oozed down and then out of his conjured throat into his ribcage where it oozed down uncomfortably close to _his soul_. He jerked again, his body once more attempting to vomit.

It did _no_ good though and cum kept pumping into him from both dicks. He started forcing swallow it so it would at least nowhere near his soul, holding back the need to vomit again. How long was this going to go on for? How much could his already too full pussy take before it burst? … Would that kill him? Perhaps… hopefully. As bad of a way as that would be to die it’d still be an end to this.

But as time _dragged_ on and he kept swallowing and swallowing, no pressure built in his pussy. Instead the cum seemed to be pouring into his middle? … Yes, the drug at summoned that too. Meaning he _wasn’t_ going to die from his pussy popping. Under different circumstances that would’ve been good thing, under these though it meant he’d have to keep suffering and swallowing its cum as his womb grew heavy with it until it finished. Hopefully it was almost done.

It wasn’t though. It kept coming and coming and coming. Though it was possible only minutes were passing, perhaps even seconds. How was he supposed to keep track of time with he was blinded by tentacle dick and suffering? If he weren’t a skeleton and thus able to breath and swallow things at the same time he would’ve drowned in its cum. Maybe one day he’d be grateful for avoiding such an ignoble and _awful_ end, right now though he just wanted _this_ to end.

Exhaustion set in, a result of his previous panic and desperate struggles. He wanted to sleep, get away from all this and rest. But not even he could sleep in these conditions. Was this better than it fucking him though? … Marginally yes. Especially since when it _finally_ finished it’d be done… (unless it wanted to go again).

Sans almost couldn’t believe it when the knots – that’s what they were called, right? – finally did soften and cum stopped pouring into him. It made his middle feel a bit heavy, perhaps it was even a little swollen too, and he was desensitized to the taste, something he wouldn’t have thought was possible.

Its dicks started sliding out; he was ready to sob and cry in relief before passing out and napping this horrible awfulness away even if only a little while. But then… they thrust right back in again, down his sore abused throat and into his pussy – still burning with awful arousal – making its cum squelch out around its dick with a horrible wet sound and awful sensation of it splashing onto the bones around his pussy.

He screamed and thrashed as it started fucking him again, just as hard and fast as before. It hurt more now though with how sore his magic was for having to accommodate its dick and knot for so long. His throat and jaw ached twice as much as well.

It _wasn’t fair_ , why couldn’t it be satisfied with just the once? … Maybe Gaster was and he’d be an end to it. … Nothing was happening though. Was Gaster even still watching? Or had he left Sans alone with the _thing_ until it was satisfied? There was no way to know, he was blind.

Sans’ struggles were just useless as before. Exhausted beyond belief however, he was eventually forced to give up – go limp – and just take it. The drug was still affecting him, another climax with building in his magic. That at least would be a few seconds of relief; he willed it come faster.

As expected it was intense when it hit, not entirely pleasurable though. He arched his body as it washed through him, temporarily blanking out his mind with sensation. But he came down feeling more exhausted and in even _more_ pain as his magic started to become overstimulated even as the drug still had it burning with arousal. How long would that last?

He sobbed uselessly, getting little relief from it without the tears. His eye sockets were numb though, the magic in them adjusted to accommodate its wretched tentacle dick sliding against them and in his skull as it fucked his mouth. Couldn’t it have just gone straight for his mouth?

He lay limp until another climax was forced out of him, leaving him even more exhausted and over stimulated. Each of its thrust in both ends hurt like hell on top of a steady throbbing pain. It came again shortly after he did. The knot setting into his pussy _hurt_ and he screamed again. And the knot his mouth was _awful_ and painful too. But thankfully it was still now even if it was pumping more foul thick cum into him, forcing him to swallow it once more as that was preferred to it possibly oozing onto his soul.

What if… this permanently fucked up – heh – his eyesight? What if this rendered him permanently blind? Or near as good as? Not only would that spell his doom – such disabilities weren’t often tolerated in the harsh world of the Underground, especially in the Capital – but he couldn’t _bare_ the thought of not being able to see anymore, especially since it would forever remind of this moment. There was nothing he do about it though if that did happen and he was too exhausted to think much on it.

Slow enough that he barely noticed it his middle grew heavier. After a while he could _swear_ it was swelling with _cum_. _Disgusting_. But there was _nothing_ he could do about it even if he’d had the energy to. So he lay there, his mind floating in a haze of exhausted misery and despair.

After a _long_ while its knots softened and he _hoped_ and _prayed_ that this was the end. To no one’s surprise he was disappointed as it resumed fucking him with vigor. He didn’t even have the energy to sob anymore. Every inch of is throat and pussy screamed with pain at each harsh thrust into them.

Despite that he eventually came again. It was more a sharp spike of pain than pleasure. He hardly cared though, his entire being was pain at this point, a little more changed nothing.

He relaxed with a wretched whimper.

His mind was pulled a little back from the exhausted fog it was under by the increase in pain once the knots set back in. He lacked the energy to keep swallowing though, meaning it oozed into his ribcage. He lacked the energy to care.

He drifted off at some point only to be woken again as it resumed raping him. His belly was heavy and _definitely_ swollen with its cum now as it oozed out of his pussy, more being forced out each time its dick filled him. Was this how he was going to die, fucked to death by a demon goo dog? If so hopefully the end would be soon.

Time held no meaning. He drifted in and out of partial consciousness, never fully aware and never truly asleep either. Pain and exhaustion was his entire world. There was no escape and there was no end. Perhaps this was his entire life, all his memories of before nothing but pleasant dreams amongst his suffering.

…

A loud buzz woke Sans it was followed by a loud metallic rattling, like a garage door closing. He groaned, not ready to wake up but in too much pain not to now that the process had started. _Everything_ hurt, even his damn eyes. Opening them revealed his vision was screwy, everything was blurry and it was impossible to make anything out.

He closed them again. As tired and as much pain as he was in he needed to take stock of his situation and figure out how to best act; he’d taught that to Papyrus now it was time to finally listen to his own advice for once.

His pussy was summoned and _hurt_ and _something_ was leaking out. He trembled and let out a sob as the feel of the demon goo dog’s dick thrusting into him came back to him with horrifying clarity. … It _wasn’t_ real though, it was gone, he wasn’t getting fucked anymore. It wasn’t worth wasting what tiny amount of energy he might have freaking out right now. He _had_ to get out before something else horrible happened to him.

He was still securely bound though and his arms locked in the straight jacket. They were brushing up against something though. He opened his eyes again – he could still almost feel the _thing’s_ tentacle dick looping through them to fuck his mouth – to see what. His vision was still blurry but the slight improvement allowed him to see that his middle was swollen; his arms were resting just above it, brushing against it as his chest rose and fell with each painful breath. He looked… pregnant. He wasn’t though, that was all… cum.

He gagged as titled his head back, holding back a sob. He could feel drying congealing cum on his legs, feet, mouth, and inside his ribcage. He needed to bathe in bleach and drown himself in it.

He dispelled his pussy, making more cum splash onto his pelvis. He whimper in disgust and despair. His middle didn’t go away though and seem to… seal itself instead. _Why_? He _needed_ it out of him _now_ even if that meant it’d splash onto his spine and get everywhere. But no matter how hard he tried to make his ecto-womb and abdomen go away they wouldn’t.

“A shame.”

Sans jerked his head to the side. A blurred figure that could only be Gaster was walking towards him. He was holding something in his real hands that once he was right next to the table, Sans could see was the metal part of the muzzle that had been on him.

“This was the only muzzle I had in your size,” Gaster said, disapproval in his voice – no doubt on his face too if Sans could see well enough to make out his expression. “And that dumb dog broke it.” He cared _more_ about the muzzle having been broken than he did about what had been done to Sans.

Tears filled Sans’ eyes. They stung, increasing his misery that much more. He shouldn’t cry about that – he’d figured out earlier that he meant less to Gaster than non-sentient mice – but… it was just the last straw on top of all the horrendous stuff he’d just suffered through. He would’ve sobbed if he could but lacked the energy for it. He wanted to go back to sleep.

Before he could drift off though Gaster’s floating hands undid the straps holding him to the table. Tears still leaking from his aching eyes, he let out a small sigh of relief as he was finally able to straighten out his stiff aching legs. Now if only he could move his arms too. Was it worth asking for the straight jacket to be taken off? … No. Gaster would decline and be annoyed by Sans’ speaking which might lead to more torment.

One of the hands tugged at the collar of his straightjacket and pulled him off the table. He whimpered but made no protest or move to stand properly, only kept up right by the hand continuing to hold the collar of the jacket.

Gaster started walking and Sans was limply carried along, feet dragging across the floor, behind him. “You’ll get a shower tomorrow if this worked else we’re going to have to do that again.”

Suddenly more awake now, Sans opened his mouth to beg for mercy but snapped it shut again, trembling. He’d _rather_ die a horrific death than go through that again so hopefully whatever was supposed to happen as result of his suffering happened – he was much too tired to even try to figure out what it might be. _That_ was the only way he’d get out of that torment. Gaster had no mercy anywhere in his soul, asking for such would only annoy him and thus would perhaps lead to more suffering.

So, he forced himself to stay quiet as he was dragged along to somewhere. He didn’t care where as long as it was away from the demon goo dog. He closed his eyes. He was tired enough that he could sleep despite being dragged along, the pain pervasive in his entire body, and protentional fate awaiting him tomorrow if Gaster didn’t get his way today.


End file.
